Relief valve



Aug. 31, 1943. w. ERNST 2,328,132

RELIEF vALvE i Filed July 26,' 1941v luz. E'

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A WALTER/.Enum ma E n p@ Ow Patented Aug. 3l, 1943 n aanmrvaLvE waiter Emu, Manni Gilead, omo, mimorto' The Hydraulic Development Corporation, Inc., I Wilmington, Del.,` a corporation of Delaware Application .my 2s, 1941. serial No. 404,219

claims' (ci. 137-53) This invention relates -to valves and, in particular, to valves which, in response to a predetermined pressure, release an outlet opening to relieve pressure therefrom. H

`This type of valve, commonly called a relief valve, substantially comprises a cylinder with two portsl and a plunger-like valve member acted upon by pressure uid admitted through one of,

said ports and continuouslyurged by a spring into position for closing the other port. ,I

These valves, as heretoforeknown, have the fdrawback `that; when using high pressureand correspondingly strong springs, the valve member vibrates violently at the attainment of the release pressure and chatters" to such an extent that not infrequently it causes breakage of delicate gauges connected` thereto.. Furthermore,'this jumping of the valve member is rather detrimental to the life o! the spring and makes it impossible to stabilize the desired pressure, in

other words, pressure variations cannot be avoid` ed with the relief valves heretofore known.

Accordingly, it is `an olject of the present invention to provide a relief valve which will overcome the above mentioned drawbacks without complicating the valve structure.

It is a further object to provide a pressure relief valve in which the force exerted by a, spring upon the valve member is supplemented by iluid pressure. t

It is another` object to provide a pressure relief valve in which, responsive to the attainment of the pressure `ior `which the valve is set, a portion of the pressure fluid causing actuation of the valve member is conveyed to a spring to support the latter in opposing the actuation of the valve member by the pressure iluid acting thereupon. 'I'hese and` other` objects and advantages of the invention will appear more clearlyfrom the following specification in connection with the accompanying drawing, in which: `Figure 1 diagrammatically illustrates a hydraulic press circuit in connection with a reli valve according to the invention. I f b i Figure 2 is a section throng. a relief valve according to the invention. f l

General arrangement In general, the valve according to the invensorber or stabilizer, thereby enabling a smooth opening of the valve and a stabilization of the valve member in its releasing position when a predetermined pressure has been reached, pre'- venting the pressure from exceeding a predeterminedvalue. u

Structural arrangement `Referring now to the drawing in detail, Figure.

1 illustrates a hydraulic press circuit ink connectionwithl a vreliei' valve according to the lnvention. I The hydraulic circuit of Figure l comprises fa main cylinder I having reciprocably mounted therein a double-acting piston 2 connccted by a lrain 3 with a platen l which in its turn comprises clamping cylinders 5. Reciprocably mounted in the clamping cylinders 5 are clamping plungers 6 connected 4to a clamping platen 1.

The clamping cylinders l communicate'with conduits! and l interconnected with each other and leading to the inlet Ila of the pressure relief valve, generally designated I I. I

The vlave II shown in Figure l communicates through conduits I2 and I3 with the inlet port of an adjustable choke or throttle Il which in its turn communicates with conduit I5 leading to a fluid reservoir or surge tank It. yThe tank Il is connected'with the suction line I1 of a constant delivery pump I l, the pressure side of which communicates with a four-way valve Il,

having a nuid connection ltoy the tank I6, a fluid` connection 2i to the upper portion of the main cylinder I, and a fluid connection `22 to the lower portion of the main Vcylinder I.`

'I'he relief valvel I is set for a desired pressure inthe clamping cylinders Band, when the clamping platen l at the downwardjstroke of the ram 3 engages the workpieceand, thereby, comes to a halt, while the ram 'I continues its downward movement, `pressure builds up in the clamping cylinders 5 which, at the attainment of a predetermined value determined by the setting of the relief valve II, causes the opening of the relief valve. Theclamping pressure in the clamping cylinders 5 may be observed'on the gauge 23. The pressure relief valve II may be constructed 11178110118 folms.

Accordingto Figure 2,'the relief valve comprises a;casing 24a with theinlet opening Ilia adapted to be connected to the pressure line 9 and leading to the vcylinder bore 25a having reciprocably mounted therein a valve member 28a which in its'turn is adapted to control an outlet t Having thus nected with an exhaust. y

'I'he upper end of the value member 26a is connected, in any convenient manner, with a disc 28a arranged in a springchamber 29a provided on top of the casing 24a and housing a spring 30a which continuously urges the valve memberl 26a into position for closing the outlet port 21a.

engaged by a disc 3 la which, by means of a screw 32a, may be adjusted so as to vary the thrust oi the spring 30a.

The spring chamber 29a has a restrictedr'co'nnection I3 with the exhaustline I 2 leading nection between said inlet port and said outlet "While the; lowenend'of the spring `30a engagesy the disc;28a,l the upper end of the spring 30a is adapted to cause said plunger to release said outlet opening.V

3. In combinationin a valve, a casing having a valve chamber with an inlet port and an outlet port, a valve member reciprocably mounted in said valve chamber 'and normally being in closing position to thereby prevent fluid conport, vsaid Avalve member being adapted in response tol a.k predetermined opening pressure at the inlet port to move into opening'position for y eiecting iiuid connection between said inlet porty ,K and said outlet port, yielding means continuouslyurging said valve member into position for When,v at the inlet port lila; apredeterminedv pressure has been obtained for which the relief valve has been set by the adjustment` ofthe screw u32a,the valve member 26a Will be'lifted so as to,"

releasethe outlet port 21a. A portion of the pressure fluid will thenV be conveyed'throughy conduits l2 and' I3 into the spring chamberlvja and will there 'act upon the central portion' ofthe 'disc'28a to supportthen action of the spring 30a. In this way the iiuidpressurer prevailingv'in the spring chamber 29a acts as shock absorbed 'and stabilizer, and 'prevents `anyviolent vibrations` or chattering of ther valve member 26a, thereby station. i

v,It will-be understood ,that Iv; desire to gcornprehend within my invention such modifications as come within thev scope ofthe claimsV and the,

invention. i

muy described invention.; l

l' having a valve bore -with an inle'tand an outlet `closingsaid outlet port, conduit means for conveyingffiuid' pressure from said outlet port to said .valve member for aiding the -thrust exerted l thereupon by said yielding means in its `tendency to move said'valve member into. closing position,

andmeans for selectively varying said last mentioned uid pressure without changing said pre'- determined opening pressure.

4. In combination in a valve, a valve casing opening, a iiuid operable plunger reciprocably mounted in said valve bore and operable to control said outlet opening, a chamber connected to saidcasing, and housing a spring acting upon a portion of said plunger extending into said chamwhat I claim asr newancl desire to secure by Let-fv y ters Patent is:

i LA valveshaving port and an outlet port, an exhaust linei connected` to said outlet vporta Vvalve member reciprocably mounted in. said vvalve chambenand operable by pressure iiuid admittedthrough said inlet port' to release saidvoutlet ,.DQrt, yieldn ing meansv continuously urging `said valvef member-into position :for closing'said4 outlet port,` choke. means insaid exhaust'line, Iand conduit means communicating lwith said ,exhaustlline at, a point between said outlet-port and said choke means andadapted toconvey pressure fluid to saidvalve member in. @direction .to aid.v said yielding ymeans in its tendency to movesaid valve member into said closing position..l

. 2. In a hydraulic circuit, avalve casing-having a borevwithan inlet and van "outlet opening, a Vplunger reciprocablymounted in lsaid bore and normally closing, said outlet opening, said` plunger being operable to release. saidoutlet opening in response' toY a predeterminedp'resj-v sure at said inlet opening, 'achamber' associated., with said casing"r and housing lyielding means' acting upon said yplunger so as 'tol continuously urge the same into position for lclosingjsaid youtlet 'openin'g, 'a low pressurekline connected with said 'chamber and said outlet opening andk adapted to convey fluid pressure to said chamber lower than the pressure at said inlet opening for exerting pressure onfsaid4 plungerin the same 'a chamber with inlet...

ber,v said spring being, arranged Vfor continuously urging said plunger into positionv for closing said outlet opening, conduit' ymeans connected to said outlet opening.and` comprising a choke, and a hydraulic connection between said chamber and a point of said conduit means, lo'- cated'between said choke and saidfoutlet opening,

I having-achamber with an inlet and an outlet. opening, a valve member reciprocably mounted yin said chamber and normally-*closing said outlet opening, said valvemember being adapted in response to a predetermined iluid' pressure, at said inlety opening to release said outlet opening for releasing pressure fluid therethrough, yielding -means being arranged in a chamber form-.-

, ing apart of said valve casing, conduit means continuously'` establishing fluid connection between-said outlet opening and said last'mentioned chamber and responsive upon movement of, said :valve member into its releasing position for directing a portion of said pressure fluid to act on said valvev member in the same vdirection as the thrust exerted by said yielding means upon said valve lmember,l to supplement the thrust of said yielding meansand means arranged outside said conduit means for varying the amount of the pressure huid entering said conduit means without changing said predetermined uid pressure which causes said valve member to release said outlet opening.

. 1 a f WALTER ERNST. 

